Research and development work in the laboratories of Worley and co-workers has proceeded with the goal of producing novel biocidal compounds (for example, see review articles Worley, S. D., Williams, D. E., “Halamine Water Disinfectants”, CRC Crit. Rev. Environm. Cntrl. 1988, 18, 133; Worley, S. D., Sun, G., “Biocidal Polymers”, Trends Polym. Sci. 1996, 4, 364; Kenawy, E., Worley, S. D., Broughton, R. M., “The Chemistry and Applications of Biocidal Polymers, A State of the Art Review”, Biomacromolecules 2007, 8, 1359, and the references incorporated therein). All of the work has focused upon a class of compounds known as organic N-halamines, which are generally heterocyclic monomers or polymers containing nitrogen-halogen bonds. The most stable of these compounds with regard to the release of bleaching free halogen in aqueous solution are those containing N—Cl covalent bonds stabilized by electron-donating substituents, e.g. alkyl groups, such as methyl groups, attached to the carbon atoms in the structures directly linked to the nitrogen atom containing the chlorine atom. The mechanism by which these N-halamine compounds inactivate pathogenic microorganisms is through direct contact in which the N-halamine donates its halogen atom to the biological cell, wherein the cell is inactivated through an oxidation process. If the N—Cl bond on the N-chloramine is sufficiently strong, the disinfection process will be slower than for “free chlorine”, the antibacterial agent which is present in household bleach. However, if free chlorine is not appreciably released from an N-chloramine into aqueous media, then undesirable chemical processes, such as corrosion and bleaching, will be minimized.
There is a need for new N-halamine biocidal materials which maintain their disinfection and detoxification properties for long periods of time, load higher amounts of oxidative halogen than those disclosed before, and are resistant to degradation in sunlight. Several N-halamine surface coatings containing hydantoin moieties have been developed; e.g., see U.S. Pat. Nos. 6,969,769 B2; 7,335,373 B2 and 5,882,357 A; these patents, and articles cited above, are hereby incorporated by reference for all of their teachings. However, past biocidal materials developed for surface coatings which contained the hydantoin moieties have the limitation that the hydantoin moiety is tethered to the surface through the imide nitrogen atom of the hydantoin ring, thereby leaving only the amide nitrogen atom of the hydantoin ring as a binding point for oxidative halogen, which limits the amount of biocidal halogen contained in the material.